What are the main sources of non-metallic inclusions in steel?

1 endogenous inclusions. It refers to the oxide formed by oxidation of elements during smelting, the deoxidation product formed during deoxidation, and the compound which is not melted in steel due to temperature drop and composition segregation during solidification.

2 foreign inclusions. Refers to the inclusions in the molten steel that are eroded and eroded from the lining and casting equipment refractory materials during the smelting and pouring process, the dirt brought in by the furnace material, and the slag mixed into the molten steel.